The Supreme Court might eventually need to decide how much free speech the Supreme Court can tolerate. A federal judge throws out a law barring protest banners and processions on the high court’s grounds, rulings it’s so broad it could criminalize preschool students parading on a field trip. (ASSOCIATED PRESS / Evan Vucci, File)

WASHINGTON (AP) — In a case that could end with the Supreme Court deciding how much free speech to allow on its own doorstep, a federal judge has thrown out a law barring processions and expressive banners on the Supreme Court grounds.

The law is so broad, the judge said, that it could criminalize preschool students parading on their first field trip to the high court.

Harold Hodge Jr. was arrested on the Supreme Court plaza in January 2011 while wearing a sign that criticized police treatment of blacks and Hispanics.

He claimed the law violates the constitution, and U.S. District Judge Beryl Howell agreed. She ruled Tuesday that the statute ran afoul of the First Amendment’s free speech protections.

The Rutherford Institute, a civil liberties organization which challenged the law on Hodge’s behalf, said that ruling “throws a lifeline to the First Amendment at a time when government officials are doing their best to censor, silence and restrict free speech activities.”

A spokesman for the U.S. Attorney’s office in Washington said the office was reviewing the decision.

If the Obama administration appeals, the case could reach the Supreme Court, historically the guardian of free speech rights. That could create the ultimate not-in-my-backyard case, except it would be more about the court’s front yard.

In 2011, Hodge was on the Supreme Court plaza wearing a sign that said, “The U.S. Gov. Allows Police To Illegally Murder and Brutalize African Americans And Hispanic People.”

After Hodge refused a Supreme Court police officer’s order to leave the plaza, he was arrested and given a citation for violating the law.

That law makes it a crime to “parade, stand, or move in processions or assemblages,” or to display a “flag, banner, or device designed or adapted to bring into public notice a party, organization, or movement,” at the high court’s building or grounds.

The charge eventually was dropped in a deal with prosecutors in which Hodge agreed to stay away from the Supreme Court grounds for six months. But after that period was up, Hodge decided he wanted to come back, and this time he was backed by lawyers.

Last year, Hodge sued and said he planned to return to the plaza and picket, hand out leaflets, sing, chant and make speeches.

In a 67-page opinion, Howell, an appointee of President Barack Obama, said that the law’s prohibitions on signs and processions were both overly broad. She wrote that the government “essentially conceded” during oral arguments that the ban on signs would prohibit a group of tourists assembling on the Supreme Court plaza, all wearing T-shirts to bring public notice to their organization — be it a church, school or other group.

The ban on processions, the judge wrote, “could apply to, and provide criminal penalties for, any group parading or assembling for any conceivable purpose, even, for example, the familiar line of preschool students from federal agency daycare centers, holding hands with chaperones, parading on the plaza on their first field trip to the Supreme Court.”

The government argued that the law was a “reasonable limitation on speech,” because it furthered two significant interests: permitting unimpeded access of visitors to the Supreme Court, and preserving the appearance of the court as a body not swayed by external influence.

Howell wasn’t buying it.

She said that first interest wasn’t significant enough to justify the ban. As for the second, “It is hard to imagine how tourists assembling on the plaza wearing T-shirts bearing their school’s seal, for example, could possibly create the appearance of a judicial system vulnerable to outside pressure.”

Should the Supreme Court decide the case, it won’t be the first time the justices have ruled on a challenge like this.

Howell went into detail on the history of the no-protests law, which was passed in 1949 and patterned after a law that applied to the U.S. Capitol grounds.

The Capitol grounds law was challenged by a coalition of women against the Vietnam War, and in 1972, a three-judge panel of the U.S. District Court in the District of Columbia declared it unconstitutional. The Supreme Court affirmed the decision.

In 1981, the federal appeals court in Washington threw out the “nearly identical” law applying to the Supreme Court, saying it was “repugnant to the First Amendment of the Constitution. ... We believe that it would be tragic if the grounds of the Supreme Court, unquestionably the greatest protector of First Amendment rights, stood as an island of silence in which those rights could never be exercised in any form.”

But the Supreme Court took a narrower view. The justices agreed that the law was unconstitutional as it applied to sidewalks surrounding the court, but they did not decide on the constitutionality of the law as a whole. Now, the current practice is that protesters have to stay on the sidewalk, but can’t be on the marble plaza at the foot of the court’s front steps.

In an opinion concurring in part and dissenting in part, Justice Thurgood Marshall said the Supreme Court should have gone further. The late justice said he “would not leave visitors to this court subject to the continuing threat of imprisonment if they dare to exercise their First Amendment rights once inside the sidewalk.”